Pitch perception and frequency-following responses elicited by lexical-tone chimeras.

OBJECTIVE: Previous research has shown the usefulness of utilizing auditory chimeras in assessing a listener's perception of the envelope and fine structure for an acoustic stimulus. However, research comparing and contrasting behavioral and electrophysiological responses to this stimulus type is scarce. DESIGN: Two sets of chimeric stimuli were constructed by interchanging the envelopes and fine-structures of the rising/yi(2)/and falling/yi(4)/Mandarin pitch contours that were filtered through 1, 2, 4, 8, 16, 32, and 64 frequency banks. Behavioral pitch-perception tasks were administered through a two-alternative, forced-choice paradigm. Electrophysiological responses were measured through scalp-recorded frequency-following responses (FFRs) to the lexical-tone chimeras. STUDY SAMPLE: Twenty American and twenty Chinese adults were recruited. RESULTS: A two-way analysis of variance showed significance (p < 0.05) within and across the filter bank and language background factors for the behavioral measurements, while the frequency-following response demonstrated a significance only across the filter banks. CONCLUSIONS: Perceptual importance of envelope cues increases starting from 16 filter banks, while the FFR accuracy and magnitude decreases with increasing number of filter banks. These results can be useful in assessing experience-dependent neuroplasticity and in designing speech processing strategies for cochlear-implant users who speak tonal or non-tonal languages around the globe.

Recording frequency-following responses to voice pitch in guinea pigs: preliminary results.

Although scalp-recorded frequency-following response (FFR) to voice pitch has shown great potential to examine pitch processing mechanisms in human participants and animals, few reports have addressed the test-retest reliability of such a response in an animal model. The purpose of this study was to investigate the feasibility and reliability of recording such a response in an animal model and to evaluate the extent to which the response could be separated from background noise. A Chinese monosyllable with a rising pitch was used to elicit the FFR to voice pitch in four guinea pigs. Four objective measures (Root-Mean-Square, Amplitude, Tracking Accuracy, Frequency Error, and Slope Error) were computed from recorded brain waves and were used to examine the phase-locking magnitude and test-retest reliability of the response. Results demonstrated that the animal model produced FFR trends that were repeatable, reliable, and significantly different from responses to the background noise.

Increased risk of Eustachian tube disorders in patients with sleep-disordered breathing.

Sleep-disordered breathing (SDB) and Eustachian tube disorders (ETDs) share the same risk factors. The specific aim of this study was to determine the correlation between these 2 conditions and to determine whether treatments for SDB reduce the risk of ETD.This is a retrospective and large population-based cohort study. According to Taiwan's National Health Insurance Research Database, out of 1,000,000 insured patients, 24,251 patients were newly diagnosed with SDB from year 2000 through 2009. The control group for this study comprised 96,827 patients without SDB who were randomly selected from the same database at a ratio of 1:4, frequency matched for sex, age, and index year of SDB. The incidence of developing ETD was compared between these 2 groups; the main covariates were demographic data, interventions, and medical comorbidities.There was an increased risk of developing ETD among the SDB cohort compared with the control group (hazard ratio = 1.51, 95% confidence interval = 1.41-1.63). Compared with SDB patients who did not receive treatment, those who received the treatment, that is, pharyngeal or nasal surgery, CPAP, or multiple modalities (both surgery and CPAP), had a significantly reduced risk of developing ETD.This study showed that patients with SDB are at an increased risk of developing ETD and other comorbidities. The risk of developing ETD can be reduced by implementing prompt treatment for SDB. Multidisciplinary evaluation including ETD should be conducted in the management of patients presenting with SDB.

Development of Subcortical Pitch Representation in Three-Month-Old Chinese Infants.

This study investigated the development of subcortical pitch processing, as reflected by the scalp-recorded frequency-following response, during early infancy. Thirteen Chinese infants who were born and raised in Mandarin-speaking households were recruited to partake in this study. Through a prospective-longitudinal study design, infants were tested twice: at 1-3 days after birth and at three months of age. A set of four contrastive Mandarin pitch contours were used to elicit frequency-following responses. Frequency Error and Pitch Strength were derived to represent the accuracy and magnitude of the elicited responses. Paired-samples t tests were conducted and demonstrated a significant decrease in Frequency Error and a significant increase in Pitch Strength at three months of age compared to 1-3 days after birth. Results indicated the developmental trajectory of subcortical pitch processing during the first three months of life.